[ryanturner]

I have been getting a lot of use out the scotchbright wheel I have mounted on my bench grinder, to the point of wearing a grove right down the center of it. While cleaning up the edges of the skins for the horizontal stabilizer this morning, I noticed that the groove has gotten so deep that the sides of the groove are making contact with the top and bottom of the skin and removing some of the alclad. The groove is about 1/8 inch deep.

I am still working on the first portion of the empennage kit, so this is still all very new to me. Is this normal wear for a scotch bright wheel? Should I be worried about the alclad removal?

 

[Guy Prevost]

It might be too late for this wheel, but if you move the parts diagonally across the wheel you won't groove it. It will last for several airplanes this way. If you try the diagonal trick now with the groove in the wheel, you will wind up eating the part. When you can't move the part diagonally (due to its shape), try and use a different part of the wheel each time to keep wear even.

You can probably save your wheel by dressing it with an old file until it is flat across the front again. This will make a huge mess, but is cheaper than replacing the wheel.

 

[Dan Langhout]

40-60 Grit Paper on a block . . . . .

. . . . does a really good job of dressing down a wheel to get rid of a groove. I tend to use the 2-inch Scotchbrite wheels on a die grinder - and they groove terribly! The course grit paper on a block seems to remove material on the wheel without much effect on the sandpaper. I have used old files for this task but the wheel seems to wear the file as much as the file wears the wheel!

FWIW.

 

[9GT]

I like to have a groove in mine for polishing up the edges. When it gets too deep, I move over a little until its finally full of groves too deep to use. Then I dress it down and start all over again.

 

[rv7charlie]

After going through the same frustrations using the wheel, I discovered that a common belt sander clamped to the workbench works just as well (often better) than the wheel. I think I used 120 grit for most of the sheet stock, with a touchup using something finer if it still felt rough. For thicker stuff with deep shear marks, I'd use bigger grits to start. In addition, I found that I could clamp large sheets to the work bench & 'free hand' the edges with the sander. I used my 'standard' size (3"x21", IIRC) but a smaller one would obviously be easier to handle in free hand mode. If you want to try it, be sure to practice 1st on scrap. I found that you must be careful to hold the work so it's being pulled across the cutting surface; never pushed (causes it to chatter).

Charlie

 

[Ironflight]

After going through the same frustrations using the wheel, I discovered that a common belt sander clamped to the workbench works just as well (often better) than the wheel. I think I used 120 grit for most of the sheet stock, with a touchup using something finer if it still felt rough. For thicker stuff with deep shear marks, I'd use bigger grits to start. In addition, I found that I could clamp large sheets to the work bench & 'free hand' the edges with the sander. I used my 'standard' size (3"x21", IIRC) but a smaller one would obviously be easier to handle in free hand mode. If you want to try it, be sure to practice 1st on scrap. I found that you must be careful to hold the work so it's being pulled across the cutting surface; never pushed (causes it to chatter).

Charlie

I constantly use my belt sander to make pieces nice and straight - but I always end up polishing the edges with the scotchbrite wheel (or disks on the angle grinder) to give a smooth edge. I'm not sure 120 grit would give me the amount of polish I like to see on edges. My preference of course.

Paul

 

[L.Adamson]

I constantly use my belt sander to make pieces nice and straight - but I always end up polishing the edges with the scotchbrite wheel (or disks on the angle grinder) to give a smooth edge. I'm not sure 120 grit would give me the amount of polish I like to see on edges. My preference of course.

It was the same for me. I used two 1" belt sanders with different grits. And then the Scotchbrite wheel, or blue 2" scotchbright disks on an angled air grinder.

L.Adamson --- RV6A